Number of hours spent in variety of sitting tasks 5 y ago recalled. Calendars were used to assist recall. Structured questionnaire based on validated Hawaii Cancer Research Survey and Australian Health Survey.

Compared with men who reported a lifetime of heavy manual labor, men whose occupation involved mainly sitting had a 40% increased risk of prostate cancer (OR, 1.39; 95% CI, 1.11-1.75). Association with prostate cancer death was nonsignificant.